1. Field of the Invention
The present invention relates to automatic washing machines employing vertical axis agitators which provide a toroidal rollover motion to clothes and wash fluid within the machine, and is particularly pertinent to double acting agitator constructions using upper, auger portions as well as lower, oscillating portions.
2. The Prior Art
It has been discovered that a very efficient movement pattern for clothes within an automatic washing machine of the vertical axis agitator type is one of toroidal rollover. The prior art is exemplified by U.S. Pat. Nos. 3,987,508, 3,987,651 and 3,987,652, all issued to the assignee of the present application. Such rollover action is accomplished by urging clothes down the agitator barrel along a unidirectionally rotating auger portion, radially outwardly along oscillating agitator vanes in the lower portion of the wash receptacle, upwardly along the wall of the wash receptacle, and inwardly to the barrel at the surface of the wash fluid, forming a toroidal pattern in the wash zone and washing liquid. When the washing basket is heavily loaded with clothes the load crowds the agitator in the basket and may affect adversely the achievement of a full rollover action. With conventional agitators not having any rollover augmentation features only the bottom portion of the tightly packed load is scrubbed, resulting in a very poor and uneven cleaning action.
U.S. Pat. Nos. 1,543,323, 1,688,031 and 1,754,626 disclose automatic washing machines having raised rims on oscillating circular skirts. U.S. Pat. Nos. 1,629,391 and Re. 18,280 show non-oscillating flow deflectors in the bottom of wash receptacles of automatic washing machines. U.S. Pat. Nos. 1,632,866, 1,665,959, Des. 100,861, Des. 105,517, and Des. 127,576, and French Pat. No. 1,020,189 show agitators having generally circular skirts with upward convolutions in the circumferential direction thereon.
A prior art agitator device had a skirt portion and generally upright vanes having a wavy configuration throughout their vertical extent. Attached to a chordal section of the agitator skirt between each of the upright vanes was a flat or planar, crescent-shaped cam. Oscillation of the agitator and the crescent-shaped cams thereon in a body of water produced some additional agitation, the added agitation being directed generally in a vertical direction.